FASH 15 textiles

finishing

finishing—an overview

finish—any process that is done to fiber, yarn or fabric either before or after fabrication to change:

• appearance—what is seen• hand—what is felt• performance– what fabric does

all finishing processes add to cost

finishing—an overview

fabric production—fiber processing

EXAMPLE:cotton polyester blend

•cotton fibers are processed separately from polyester fibers

• polyester produced as filament tow, crimped, cut or broken into staple fibers

• cotton needs considerably more processing—grown, picked, ginned, baled, shipped, grade assessed

fabric production—yarn processing

fibers are aligned, blended & twisted•cotton & polyester bales are opened •fibers are loosened and aligned•cotton bales blended to ensure fabric performance and quality•fibers often combined in drawing or roving stage•once fibers are blended, appropriate amount of twist is added to yarns•spun yarns wound on bobbins•shipped to mill for fabric production

fabric production—yarn preparation

involves several steps•sizing (mixture of natural starches & synthetic resins) coats warp yarns to reduce abrasion & tension of weaving•fabrication follows sizing—fabric woven, knitted or created in some other manner•preparation & pretreatment of fabric next—

• improving absorbency• reducing shrinkage• removing impurities• whitening

fabric production—fabric preparation

handling —refers to the physical form of fabric during finishing—width, length & fabrication

singeing—burns any fiber ends projecting from surface of fabric

desizing—sizing added to warp yarn removed

cleaning—warp sizing, dirt & oil are removed

scouring—general term referring to removal of foreign matter or soil from fabric prior to finishing or dyeing

fabric production—fabric preparation

bio-polishing—use of cellulase enzyme treatment to remove fuzz from spun cellulosic yarns

bleaching—process of whitening fibers, yarns, or fabrics by removing irregular natural color

optical brighteners—also used to whiten off-white fabrics—not bleaches; mask yellow by absorbing light

mercerization—treating cellulosic fabric or yarn with an alkali to increase luster, strength, and affinity for dyes

• tension• slack

fabric production—fabric preparation

ammoniating finish—less expensive alternative to mercerization used on cotton & rayon; treated with weak ammonium solution at high temps

coloration—color normally added at this stage

special purpose finishes—usually follow dyeing to avoid interference with fiber dye absorption; wrinkle resistance, soil-release, & fabric softening appropriate for cotton/poly blend

drying—especially frequent with cellulosics to minimize mildew & weight

fabric production—fabric preparation

tentering—supplies lengthwise & crosswise tension to fabric while it dries to produce uniform length & width

fabric production—fabric preparation

tentering—supplies lengthwise & crosswise tension to fabric while it dries to produce uniform length & width

loop drying—drying fabrics with soft finish (towels & knits) without tension on loop frame

heat setting—fabric placed on tenter frame and passed through oven to set and special purpose finishes

calendaring—mechanical finish performed by series of rollers between which fabric passes; simple, friction, moire, schreiner, embossinghttp://www.youtube.com/watch?v=0jjHPHj9EJA

fabric production—reworking

includes inspecting fabric for defects & flaws

fabric inspection—done by moving fabrics over an inverted frame in good light

repairing—corrects flaws marked by inspectors when economically feasible

• Broken yarns clipped• Snagged yarns worked into fabric• Defects marked so adjustments can be made

finishing steps for wool

crabbing—finishing process used to set wool fabrics; immersed in hot water then cold water & passed through rollers

decating—produces a smooth, wrinkle-free finish and lofty hand on woolen & worsted fabrics; comparable to steam ironing

carbonizing—treatment of wool yarns or fabrics with sulfuric acid; destroys plant matter and allows for more level dyeing

pressing—woolen fabric placed between metal plates that steam & press

environmental concerns & sustainability

finishing transforms a harsh, unattractive fabric into an attractive one—environmentally the impact can be significant

uses significant quantities of energy & water, potentially hazardous chemicals

systems are in place for air-pollution control, pollution prevention, & pollution reduction

• less hazardous chemicals used • reclaim & reuse of chemicals• excess use of chemicals, water & energy

being regulated